Dianne's teacher has a chunk of dry ice for the class to look at. Dry ice is a kind of frozen gas—it is very cold. The teacher w
arns her class not to touch it. When Dianne holds her hand near it, it feels like the dry ice is radiating cold. What is really happening? A) Heat energy from Dianne's hand is being transferred to the dry ice even though she is not touching it.
B) Chemicals in the dry ice are tricking Diane's nerves into thinking she feels cold.
C) Cold energy from the dry ice is being transferred to Diane's hand even though she is not touching it.
D) Small pieces of the dry ice are breaking off and hitting Diane's hand, making it feel cold.
A) Heat energy from Dianne's hand is being transferred to the dry ice even though she is not touching it.
Explanation:
In this example, we learn that Dianne feels cold when she holds her hand close to the dry ice. In fact, Dianne feels as it the cold is moving from the dry ice to her hand. However, this is not what is happening. Changes in temperature occur when heat is transferred from a warm body to a colder one. Therefore, what is actually occurring is that heat energy from Dianne's hand is being transferred to the dry ice even though she is not touching it, and this makes her feel cold.
"The padding around the goal post increases the time of the collision between the player and the post, which decreases the force exerted to bring the player to a stop"
